Adrenocorticotropin-Producing Pituitary Carcinoma with Expression of c-erbB-2 and High PCNA Index: A Comparative Study with Pituitary Adenomas and Normal Pituitary Tissues.

Pituitary carcinomas are very rare neoplasms with a poor prognosis. We report a case of Cushing's disease resulting from a pituitary carcinoma in a 22-yr old female, who died of massive hepatic failure. At autopsy, there was invasion of the parasellar structures and vasculature by the tumor, which stained positively only for ACTH. There were two metastatic nodules in the liver, which also stained positively for ACTH. When compared to other cases of Cushing's disease (n = 52), other pituitary adenomas (n = 292). and normal pituitary tissues (n = 21), the pituitary carcinoma was the only one with c-erbB-2 membrane staining in both the sellar-located tissue and liver metastasis. C-erbB-2 staining was present in the cytoplasm of a variable number of cells in 40% of the invasive adenomas (n = 103), while only 1.2% of the noninvasive tumors (n = 241) expressed this protein (p < 0.001). No particular immunohistological type preferentially expressed this protein. In normal pituitary tissues, 10% of the cells expressed cytoplasmic c-erbB-2. A higher index of proliferating cell nuclear antigen (PCNA) in the primary tumor and liver metastasis (10%) was also found compared to other ACTH-secreting adenomas (invasive, 3.4 -t 1 S% vs 1 ii +/- 1.5% in noninvasive) and other pituitary tumors (invasive, 2.9 +/- 1.5% vs 1.5 +/- 1.3% in noninvasive). The PCNA index was significantly higher in invasive tumors than in noninvasive adenomas (p = 0.004). PCNA staining was negative in normal pituitary tissues. Staining for p53, pRB and p(2ras) was negative in the carcinoma and liver metastasis. We suggest that the c-erbB-2 membrane pattern and a higher PCNA index may indicate a worse prognosis in adenohypophyseal neoplasia.

Insulin-Like Growth Factor I in Human Thyroid Tissue: Specific Localization by Immunohistochemistry and In Situ Hybridization.

Insulin-like growth factor I and II (IGF-l and IGF-ll) have been implicated in the replication of normal thyroid follicular cells in vitro. This study evaluates the distribution and abundance of immunoreactive IGF-l by histochemical analysis in human thyroid tissue with different histopathologic characteristics. We used two types of highly specific and sensitive polyclonal rabbit anti-IGF-l antibodies and one monoclonal antibody (MAb) with the immunoperoxidase technique on sections of 25 glands harboring adenomatous goiter; 11 glands with follicular adenoma (FA); 45 glands with thyroid carcinoma of papillary, follicular, and undifferentiated types; and 18 glands with Graves' disease. Immunoreactive IGF-l was present in some thyroid follicular cells of all thyroid tissues examined. The percentage of cells staining positively varies among the different processes, being lowest in normal thyroid tissues and highest in all thyroid carcinomas. The cytoplasmic pattern of IGF-l immunoreactivity also varied among the different thyroid conditions. Furthermore, using nonradioactive in situ hybridization (ISH) we detected IGF-l mRNA in the thyroid cells of adenomatous goiter. The expression was higher in the histologically hyperplastic areas. These findings provide further support for an autocrine and/or paracrine role of IGF-l in the function and/or growth of normal thyroid follicular cells and suggest that IGF-l may play a role in the dysfunctional growth of thyroid follicular cells in adenomatous goiter, thyroid carcinoma, and Graves' hyperthyroidism.